Power system

ABSTRACT

A power system is designed for providing reliable electrical power to a telecommunications facility and/or associated devices. The system includes a DC bus adapted to receive electrical power from a primary energy source. A switch is provided for switching from the primary energy source to a secondary energy source. Additionally, the system includes one or more capacitors electrically connected into the DC bus. The one or more capacitors hold a charge so that power is maintained to the DC bus as a switch is made from the primary energy source to the secondary energy source.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims priority pursuant to 35U.S.C. Section 120 from U.S. patent application Ser. No. 11/459,419filed Jul. 24, 2006, which is a continuation of U.S. patent applicationSer. No. 11/263,736, filed Nov. 1, 2005, issued Aug. 29, 2006 as U.S.Pat. No. 7,098,548, which is a continuation of U.S. patent applicationSer. No. 11/079,984, filed Mar. 15, 2005, issued Jan. 31, 2006 as U.S.Pat. No. 6,992,401, which is a continuation of U.S. patent applicationSer. No. 10/886,345, filed Jul. 7, 2004, issued Apr. 12, 2005 as U.S.Pat. No. 6,879,052, which is a divisional of U.S. patent applicationSer. No. 10/298,074, filed Nov. 15, 2002, issued Nov. 1, 2005 as U.S.Pat. No. 6,960,838.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

In general, this invention relates to a system for providing electricalpower. More specifically, this invention is directed to a systemparticularly adapted to provide reliable electrical power for theoperation of a remote telecommunications facility.

Although it may be utilized in numerous applications, this invention isspecifically adapted to provide power for the continuous operation of aremote telecommunications facility. With its core technologysubstantially composed of digital components, the telecommunicationsindustry is heavily dependent on the continued supply of reliableelectrical power. The critical nature of the functions performed byremote telecommunications facilities further emphasizes the need for adependable power supply.

Most telecommunications facilities rely on a commercial power utilityfor electrical power and employ traditional devices, such as atransformer and switchgear, to safely receive and use the electricalpower. To insure the facility's power supply is not interrupted, such asin the case of a black-out or other disturbance in the commercial powersystem, many telecommunications facilities have a system for providingbackup power. Although various designs are used, many backup systemsemploy a diesel generator and an array of batteries. If power from thecommercial utility is lost, the diesel generator takes over to supplypower, and the battery array insures that power is maintained during thetime it takes to switch from utility-supplied power togenerator-supplied power. If the generator also fails, such as due to amechanical malfunction or to the depletion of its fuel source, then thebattery array is able to provide power for an additional period of time.

There are several disadvantages inherent in the current manner in whichpower is supplied to telecommunications facilities. First, the cost oflocal electrical utility service has risen dramatically in recent yearsand, by all accounts, will continue to rise. Thus, the cost of localelectrical utility power is a large component of the facility's overallpower expenses. Next, as the facility's power demands have increased,the number of batteries required to provide an adequate amount of powerfor a reasonable period of time has also increased. Clearly, thecomponent cost of the system increases with the greater number ofbatteries required. In addition, the greater number of batteriesrequired has significantly increased the space required to house thebackup system, which has increased the spacial cost of the systems.Finally, it is known that generators suffer from certain reliabilityproblems, such as failing to start when needed because of disuse orfailed maintenance. Therefore, the reliability of the backup systemscould be improved.

The power system of the present invention overcomes these disadvantagesby providing reliable electrical power that is not initially dependenton a commercial electrical utility and that does not employ an array ofbatteries. The system, therefore, is more cost efficient and requiresless space than the present manner of providing power to facilities. Theinvention employs redundant sources of power, and thus, isuninterruptible. Also, the system employs power generating componentsthat have less of an impact on the environment than the current mannerin which power is supplied. Moreover, the system may be constructed at amanufacturing site and then moved to the facility. Thus, the system ofthe present invention provides power to a telecommunications facility ina manner that is less expensive, that requires less space, that ismovable, and that is environmentally friendly.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention are directed to a power systemdesigned for providing reliable electrical power to a telecommunicationsfacility and/or associated devices. The system includes a DC bus adaptedto receive electrical power from a primary energy source. A switch isprovided for switching from the primary energy source to a secondaryenergy source. Additionally, the system includes one or more capacitorselectrically connected into the DC bus. The one or more capacitors holda charge so that power is maintained to the DC bus as a switch is madefrom the primary energy source to the secondary energy source.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The present invention is described in detail below with reference to theattached figure, wherein:

FIG. 1 is a schematic diagram of the present invention without thesensing/control mechanism.

FIG. 2 is a functional block diagram of the major components of thepresent invention; and

FIG. 3 is a block diagram showing the physical relationship of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention includes both a system and a method for providingreliable electrical power to a facility, and specifically to atelecommunications facility. The system provides redundant sources ofelectrical power including a number of microturbine generators and anumber of proton exchange membranes (PEMs). The system also includes anumber of capacitors to provide power during the time it takes to switchbetween power sources. By employing these components, the system avoidsthe need for an array of batteries and is more cost efficient than thecurrent method for providing power to telecommunications facilities.

The present invention is best understood in connection with theschematic diagram of FIG. 1-3. In FIG. 1, the power system of thepresent invention initially comprises a number of microturbinegenerators 10. A turbine includes a rotary engine actuated by thereaction or impulse or both of a current of fluid, such as air or steam,subject to pressure and an electrical generator that utilizes therotation of the engine to produce electrical power. Microturbinegenerators are a recently developed technology and have not beenemployed to provide power to a telecommunications facility. Amicroturbine is smaller and more compact than more common turbines andcreates a lower amount of harmful emissions than both more commonturbines and diesel generators. A microturbine generator includes asystem for receiving fuel, a microturbine for converting the fuelreceived to electrical power and a digital power controller. Thus, amicroturbine generator is able to utilize a fuel source such as naturalgas or propane to produce electrical power. One microturbine generatorthat is suitable for the present invention is the Capstone 60MicroTurbine™ system produced by the Capstone Turbine Corporation ofChatsworth, Calif. As is understood by those in the art, the number ofmicroturbine generators used in the inventive system depends on theamount of power required by the destination facility.

The present invention is designed to provide fuel from two differentsources to microturbine generators 10. Initially, microturbinegenerators 10 are fueled by natural gas. The natural gas is received inprimary fuel valve 20 which is coupled to primary fuel pipe or line 30.Pipe 30 is also coupled to a series of valves 40, and each of valves 40is also coupled to an input of a corresponding mixing box 50. The outputof mixing boxes 50 is coupled to the input of one of microturbinegenerators 10. Microturbine generators 10 may also be powered by propanestored in a local storage tank 60. The propane is received throughbackup fuel valve 70 which is coupled to backup fuel pipe or line 80.Pipe 80 is also coupled to a series of valves 90, and each of valves 90is coupled to an input of mixing boxes 50. Mixing boxes 50 is operableto combine fuel received with any necessary additional components andthereafter provide appropriate amounts of fuel to microturbinegenerators 10. Mixing boxes 50 are capable of receiving and respondingto a control signal by at least opening or closing lines. In addition,valves 20, 40, 70 and 90 are also capable of receiving and responding toa control signal by at least opening and closing.

Microturbine generators 10 utilize the natural gas or propane fuel toproduce AC electrical power. The output electrical current from eachmicroturbine generator 10 is coupled to one end of a circuit breaker 100in order to protect the circuit such as, for example, if microturbinegenerator 10 causes a power surge. The opposite end of circuit breakers100 is coupled to a bus line 110 that is also coupled to switch 120. Busline 130 is coupled to the output of switch 120 and to a number ofrectifiers 140. As is known, a rectifier is capable of receiving an ACinput and rectifying or converting that input to produce a DC output.Thus, rectifiers 140 convert the microturbine-produced AC power to DCpower. The output of rectifiers 140 is coupled to bus line 150 which isconnected to the power distribution unit 160 in the destinationfacility. Power distribution unit 160 contains connections into thetelecommunications facility's power lines, and/or provides connectionsto the various telecommunications equipment. Power distribution unit 160may also contain additional circuit breakers or other power switch gearor safety devices and/or circuits, including circuits to limit thevoltage or current provided to the facility's power lines, andmonitoring/measuring equipment. A number of super capacitors 170 arealso connected to bus line 150.

The system of the present invention is also capable of receiving powerfrom a commercial utility. Utility-supplied power is received on busline 180, and a connection to ground is provided through line 190. Busline 180 is connected to one side of switch 200, and the other side ofswitch 200 is coupled to the primary side of transformer 210. As isknown, a transformer is capable of receiving an input signal on itsprimary side and producing a corresponding signal on its secondary sidethat is electronically isolated from the input signal. The secondaryside of transformer 210 is coupled to one side of a main circuit breaker220. The opposite side of main circuit breaker 220 is coupled to oneside of a number of circuit breakers 230. The opposite side of one ofthe circuit breakers 230 is connected to bus line 240; the remainingcircuit breakers 230 are available to provide electrical power foradditional applications or systems. Bus line 240 is also connected to aninput of switch 120.

The power system of the present invention also includes a number ofproton exchange membrane fuel cell modules (PEMs) 250. A PEM is a devicethat is capable of converting dry gaseous hydrogen fuel and oxygen in anon-combustive electrochemical reaction to generate DC electrical power.Because the only by-products of this reaction are heat and water, a PEMis friendly to the environment and may be used indoors and in otherlocations where it is not possible to use a conventional internalcombustion engine. In addition, unlike a battery, a PEM is capable ofproviding electrical power for as long as fuel is supplied to the unit.One PEM that is suitable for the present invention is the Nexa™ powermodule manufactured by Ballard Power Systems Inc. of Burnaby, BritishColumbia, Canada. As with microturbine generators 10, the number of PEMs250 required is dependent on the amount of power required by thedestination facility.

Hydrogen fuel is supplied to the PEMs 250 from a number of storage tanks260 located in a vault 270. Each of the storage tanks 260 is coupled toa valve 280. Each of valves 280 is coupled to a valve 290 which is alsocoupled to a pipe 300. Thereafter, pipe 300 is coupled to a series ofvalves 310, and each of valves 310 is coupled to one of the PEMs 250.The output of the PEMs 250 is connected between bus line 150 and acircuit breaker 320. As stated above, super capacitors 170 and the powerdistribution unit 160 of the facility are also connected to bus line150. The other side of circuit breakers 320 is connected to a bus line330. There are two switches connected to bus line 330. Switch 340 iscoupled to bus line 330 on one side and bus line 150 on the other side.Switch 350 is coupled to bus line 330 on one side and bus line 360 onthe other side. Unlike bus line 150, bus line 360 is only connected topower distribution unit 160 of the facility.

The power system of the present invention also comprises a number ofsensing and control mechanisms (not expressly shown) for determiningwhich fuel source to activate and which power source to engage. As isknown, the sensing mechanisms may be separate devices or may be integralto the valves, bus lines, and/or devices being monitored. Likewise, thecontrol mechanism may be a separate device, such as a programmable logiccontroller, or may be part of one of the components already described,such as the microturbine generators 10. It is also possible that thesensing and control mechanisms may be combined into a solitary mechanismthat may be a stand-alone unit or may be combined with one of thecomponents already described.

The operation of the power system may be understood by referring to FIG.2. It should be noted that the present invention is represented in FIG.2 by functional blocks. Thus, sensing/control mechanism 370 is shown asone unit when in fact the sensing and control devices actually may beseveral devices as discussed previously. Of course, all of the sensingand control devices actually may be placed together in a separate unit,such as a programmable logic controller, as shown in FIG. 2.

In operation, the sensing/control mechanism 370 initially causes valves380 (which include valves 40 and 90 shown in FIG. 1) to allow naturalgas to flow from the utility source to the microturbine generators 390and to prevent the flow of propane to microturbine generators 390.Sensing/control mechanism 370 also initiates operation of themicroturbine generators 390. In addition, sensing/control mechanism 370also causes valves 400 (which include valves 310 shown in FIG. 1) toprevent the flow of hydrogen to the PEMs 410 and causes the PEMs 410 toremain off. In this manner, microturbine generators 390 produce AC powerusing utility-supplied natural gas. The AC current produced by themicroturbine generators passes through switch 420 to rectifiers 430where it is converted to DC current. Thereafter, the DC current fromrectifiers 430 is provided to the telecommunications facility and tosuper capacitors 440. As is well known, when they first receive DCcurrent, super capacitors 440 charge to the level of the DC powerprovided.

If sensing/control mechanism 370 determines that there is aninterruption in the utility-supplied natural gas, then it will causevalves 380 to prevent the flow of natural gas and allow the flow ofpropane to microturbine generators 390. Switch 420 remains in the sameposition as before and valves 400 continue to prevent the flow ofhydrogen to PEMs 410. In this configuration, microturbine generators 390continue to generate AC power but now their fuel is propane.

If the sensing/control mechanism 370 determines that both fuel sourcesfor microturbine generators 390 have failed or that there is some otherdisturbance in the microturbine-supplied power which causes that powerto become inadequate, then sensing/control mechanism 370 will causevalves 380 to close and deactivate the microturbine generators 390.Sensing/control mechanism 370 will set switch 420 so that rectifiers 430receive AC power from the electric utility. In addition, sensing/controlmechanism 370 will keep valves 400 closed and PEMs 410 deactivated.

If sensing/control mechanism 370 determines that the electric utilityhas failed or the power it supplies has become inadequate and themicroturbine generators 390 remain deactivated, such as due to a lack offuel or a malfunction, then sensing/control mechanism 370 will causevalves 400 to open which allows hydrogen to flow to PEMs 410.Thereafter, the control mechanism will activate PEMs 410. In this mannerthe PEMs 410 provides DC power to the telecommunications facility and tosuper capacitors 440.

In each of the above scenarios, super capacitors 440 provide electricalpower during the time it takes for the control mechanism to switch fromone power source to another. Thus, super capacitor 440 must have adischarge time greater than the longest time required to switch betweenpower sources. One super capacitor that is suitable for this inventionis manufactured by Maxwell Technologies located in San Diego, Calif.

Referring now to FIG. 3, significant portions of the present inventionmay be enclosed in a modular, weatherproof container, indicated by thenumeral 450, that is transportable by truck or rail. For example, all ofthe components shown in FIG. 1, except tank 60 and vault 270 with thecomponents contained therein, may be pre-assembled and pre-wired withthe sensing/control mechanism(s) and then placed in container 450 beforebeing shipped to a facility. Once at the facility, propane storage tank460 and hydrogen storage vault 470 are provided and coupled to container450. Once utility-supplied natural gas and electricity lines have beencoupled to container 450 and the output of container 450 is coupled tothe telecommunications facility 480, then the unit may be activated.

As discussed, the power system described above initially employsmicroturbine generators to provide electrical power for atelecommunications facility. The microturbine generators are compact,efficient (both in terms of space and fuel) and reliable. By relying onmicroturbine generators as the main source of power, the system avoidsboth the reliability problems and environmental hazards inherent ininternal combustion generators and the costs and environmental concernsassociated with commercial electrical power. The power system alsoprovides redundant sources of power, specifically from a commercialelectrical utility and a number of proton exchange membranes, andtherefore is uninterruptible. Finally, the system provides a number ofsuper capacitors to provide electrical power during the time it takes toswitch between power sources. By employing super capacitors and protonexchange membranes, the power system avoids the use of batteries therebysaving significant cost and space.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, all matter shown in the accompanyingdrawings or described hereinabove is to be interpreted as illustrativeand not limiting. Accordingly, the scope of the present invention isdefined by the appended claims rather than the foregoing description.

1. A method of switching energy sources used to power a generatorsystem, said method comprising: providing power to a microturbinegenerator system; opening a first valve to allow a natural gas energysource to flow to said microturbine generator system; closing said firstvalve, and opening a second valve to allow a propane energy source toflow in response to an interruption in supply of said natural gas energysource; closing said first and second valves, and opening a third valveto allow hydrogen to flow to a plurality of proton exchange membranefuel cells in response to an interruption in supply of said natural gasenergy source and said propane energy source; and maintaininguninterrupted power to said microturbine generator system via aplurality of super capacitors during each of said interruptions insupply.
 2. The method of claim 1, wherein each of said plurality ofsuper capacitors comprises a plurality of capacitors arranged inparallel.
 3. The method of claim 1, wherein said generator system existsat a telecommunications site and is used to maintain power totelecommunications equipment.
 4. The method of claim 1, wherein openingand closing said natural gas energy source and said propane energysource and said hydrogen energy source is executed via a sensing controlmechanism.
 5. The method of claim 1, further comprising an electricutility energy source.
 6. A multiple energy source power system,comprising: a microturbine generator system; a first valve, operative toopen and close a natural gas energy source to said microturbinegenerator system; a second valve, operative to open and close a propaneenergy source to said microturbine generator system, in response to achange in supply of said natural gas energy source; a third valve,operative to open and close a hydrogen energy source to saidmicroturbine generator system, in response to a change in supply of saidnatural gas energy source and said propane energy source; and aplurality of super capacitors, operative to maintain uninterrupted powerto said microturbine generator system during each of said change insupply.
 7. The system of claim 6, wherein said hydrogen energy source isused to power a plurality of proton exchange membrane fuel cells.
 8. Thesystem of claim 6, wherein said power system exists at atelecommunications site and is used to maintain power totelecommunications equipment.
 9. The system of claim 6, furthercomprising an electric utility energy source.